In recent years, the enhanced printing capability and the improved performance of an image quality of a miniature digital developing apparatus as a digital output apparatus have increased broadly due to the popularity of digital cameras. Especially, there is a strong demand for improving the quality of larger image prints and many development reports of an exposing apparatus employing a recording head with a plurality of recording elements deployed in an array for this purpose are known.
Generally, since a light emitting recording element structuring the described array-type recording head has an its own respective light emitting characteristic, when the correction of the light emitting characteristic is not adequate, optical density unevenness on an image results and is recorded when printed. As a result, it lowers the commercial value of the image. Unevenness of each recording element is generally from 20% to 40%. In order to express a photograph by continuous optical density, unevenness of each recording element has to be no more than 2%, and when a higher quality image is desired, it should be less than 1%. In regard to correction of unevenness of a recording element, for example, Japanese Patent Open to Public Inspection: Nos. H08-230235 and H10-811 disclose those techniques.
However, according to those references, following drawbacks tends to occur.
Generally, a miniature digital developing apparatus contains a chemical storage tank for a processing solution and applies the processing solution onto a recording material (hereinafter, a photosensitive material is used in many cases but is not limited to a photosensitive material) for a developing process to form an image. Generally, since heated processing solution circulates in the chemical solution tank in order to minimize the processing time, ambient oxygen easily oxidizes the processing solution and it generates a useless ingredient. This useless ingredient accumulates in the conveyance path in the developing section and is transferred onto the photosensitive material. As a result, it appears on the photosensitive material as optical density unevenness, namely dirt generated by the factor of other-than the recording of a recording head. Recently, since the duration of processing tends to be rather lengthy, it is generally when the transferring of dirt tends to occur. Other than the situation described above, unevenness caused by the development unevenness generated by evaporation of water-drops adhering in the conveyance path also appears as dirt generated by a factor other than during recording by the recording head.
Additionally, even if optical density unevenness is caused by adhesion of dirt in a development section to photosensitive material as described above and/or the unevenness of development itself, optical density unevenness is accidentally recognized to be caused by optical density unevenness associated with a recording head and a feedback to the recording head is performed.
Consequently, in the current system, when adhesion of dirt and/or development unevenness occurs, it is often an inconvenience in that optical density unevenness appears in places where no optical density unevenness exists as a result of a correction, since the correction, which should not be conducted, is performed. It is called reverse correction and occasions of optical density unevenness increases instead of decreasing.
Since in almost all cases, optical density unevenness correction is performed as part of a warm-up process before full operation of the apparatus, optical density unevenness correction is performed when the possibility of development unevenness such as dirt adhesion after an overnight down time of the apparatus. Consequently, even in a situation where an unevenness correction is unnecessary, the correction is conducted, as in the situation described above, and as a result so-called reverse correction is conducted.
Accordingly, it becomes a situation where several corrections are necessary to correct the reverse correction. Under these circumstances, since the warming-up time becomes too long, it degrades not only the operation efficiency of a miniature digital developing apparatus but also results in mental stress of the operator identical to the operations for correcting optical density unevenness are required. This can also develop into a problem which decreases operator job satisfaction.